Probably no way to guarantee a Dalmatians room, but you can certainly call and have that request added to your reservation.
When we were there over Memorial Day Weekend, we were pleasantly surprised with the bus transportation. We expected the worst having had some terrible experiences at Pop earlier in the year. The buses were running at a pretty much continuous pace (sometimes loading two buses at once for one park). We never had to wait more than 5-10 minutes for a bus to or from the resort, even with a long line (unless we chose to be waiting earlier than we knew buses were running).